Fuel cells are electrochemical devices that convert chemical potential energy into usable electricity and heat without combustion as an intermediate step. Fuel cells are similar to batteries in that both produce a DC current by using an electrochemical process. A fuel cell has two electrodes, an anode and a cathode, that are separated by an electrolyte. Like batteries, fuel cells are combined into groups, called stacks, to obtain a usable voltage and power output. Unlike batteries, however, fuel cells do not release energy stored in the cell, running down when stored energy is gone. Instead, they convert energy from a hydrogen-rich fuel directly into electricity and operate as long as they are supplied with the fuel and oxidant. Fuel cells emit almost none of the sulfur and nitrogen compounds released by conventional combustion of gasoline or diesel fuel, and can utilize a wide variety of fuels: natural gas, coal-derived gas, landfill gas, biogas, alcohols, gasoline, or diesel fuel oil. Accordingly, there is a desire to employ fuel cells to power motor vehicles as a way of reducing noxious emissions.
Methods for generating hydrogen-rich fuel for a fuel cell from petroleum-based hydrocarbons include steam reforming and partial oxidation. Between these two methods, steam reforming is disadvantageous because it requires a sizeable apparatus that requires a heat source to maintain its operation, whereas partial oxidation can be achieved in a catalytic process that utilizes a smaller reactor size than steam reforming. In addition, a catalytic partial oxidation apparatus on an automotive vehicle typically attains its operation more quickly after the engine is started than does a vehicle-based steam reforming apparatus. However, catalytic partial oxidation reactions typically occur at 900° C. to 1100° C., at which temperatures the catalytic activity often degrades and the rate of production of hydrogen and carbon monoxide declines.
There is therefore a need for an improved method for catalytic partial oxidation and for a catalyst member having improved durability.